氮化镓基共振腔发光管研究

GaN-based resonant-cavity light-emitting diode (RCLED) is a new-style light-emitting diode (LED), which consists of an active region sandwiched in an optical resonator of two reflectors. Such device possesses many advantageous properties, including narrower spectrum linewidth, superior light-emitting directionality, inherent stability, etc. The GaN-based RCLED is desirable for many practical applications. However, due to the complex device structure, the GaN-based RCLED suffers from many significant technical and theoretical difficulties, such as complicated fabrication processes, poor heat dissipation, high optical loss, inferior mode matching, etc. To solve these problems, this proposal will focus on the GaN-based RCLED, including its design，fabrication, and basic theory. The process of device heat dissipation and the mechanism of optical loss will be analyzed by theoretical simulation method. The theoretics of mode matching will be systematically studied by using thickness gradient cavity configuration and micro-luminescence technique. On this basis, the major limiting factor for device performance will be found out. A novel GaN-based thin-film RCLED with lateral-electrode configuration will be fabricated by using a unique double-transfer technique. The problems will be overcome by improving the structure parameter, including reflector, active region, lateral optical confinement layer, etc. The GaN-based RCLED with narrow linewidth, high power, small divergence angle, and wavelength stability will be demonstrated. This program is of significance for the development and applications of nitride optoelectronic devices.

GaN基共振腔发光管（RCLED）是一种将有源区置于光学谐振腔中的新型LED，具备线宽窄、方向性好、稳定性高等许多优势，有良好的应用前景。然而，由于结构复杂，其研制难度极大，并且还面临散热差、光损耗大及模式匹配困难问题。针对这些问题，本项目将围绕GaN基RCLED的设计、制备和理论研究开展工作。利用理论模拟手段对器件的热传输机理和光损耗机制进行深入分析。利用渐变腔长结构和微区发光测试技术，对器件模式匹配理论进行系统研究。在此基础上，确定器件性能受限的主要因素。利用独特的二次转移基底技术，研制出新型的正装薄膜结构器件。通过并对器件的反射镜、有源区以及侧向光限制层等结构参数的优化，解决器件散热、光损耗及模式匹配问题，获得具有窄线宽、高功率、小发散角、波长稳定的高性能GaN基RCLED器件。本项目的研究对于丰富氮化物光电子器件种类，拓展其应用领域具有重要意义。

本项目围绕GaN基共振腔发光管（RCLED）的设计、制备、测试及理论研究开展工作。取得了以下研究成果：.1．设计了适合于GaN材料的RCLED器件结构，完善了器件制作工艺流程。金属反射镜-介质膜分布布拉格反射镜（DBR）共振腔结构，避免了氮化物DBR生长的难点；垂直电极构型改善了器件的散热特性；与垂直结构LED兼容的器件工艺，保证了器件制作顺利进行，也为将来产业化应用提供了便利。.2．分析了器件的热扩散机理，利用垂直结构构型解决了蓝宝石衬底散热瓶颈，改善了器件散热问题；模拟了谐振腔反射特性、谐振模式分布，建立了模式匹配理论模型；研究了谐振腔结构及腔面光损耗对器件纵模分布、光谱宽度及发射强度的影响规律，阐明了器件发光的调控机理。.3．提出了法布里-珀罗滤波器结构介质膜DBR作为顶部反射镜的谐振腔结构，解决了长光学腔导致的多纵模发射问题，研制出了窄线宽、单纵模、波长稳定的GaN基RCLED器件。.4．实现了GaN基RCLED纵模分布、光谱宽度及发射强度的调控。谐振腔长决定着纵模位置及间距，反射镜反射率影响光谱宽度及发射强度，带有滤波结构的顶部反射镜可改变纵模数量。